KR102637494B1 - Hot melt elastomeric adhesives for low temperature applications - Google Patents

Abstract

Comprising one or more block copolymers and one or more tackifying resins, wherein the one or more block copolymers include (i) one or more blocks of polymerized alkenyl arene monomers (A blocks), and (ii) one or more blocks of polymerized conjugated diene monomers. or more blocks (B blocks) and, if appropriate, at least one polymerized conjugated diene block (C block) of low molecular weight (relative to the B block), wherein the A, B and C blocks are independent of each other with respect to composition and molecular weight. Adhesive composition may vary.

Description

Hot melt elastomeric adhesives for low temperature applications

Reference Description to Related Applications

This application claims priority to U.S. Provisional Patent Application No. 62/247,920, filed October 29, 2015, entitled "Hot Melt Elastic Attachment Adhesive for Low Temperature Applications," which claims priority to The entire contents are incorporated herein by reference.

Technology field

The present invention relates to hot melt adhesives for elastic attachments useful in the production of diapers or hygiene products. The hot melt adhesive of the present invention can be applied by spraying at significantly lower temperatures, reducing costs, minimizing adhesive decomposition, and allowing the adhesive to be applied to thin film substrates. Typical application temperature is approximately 160°C. Adhesives of the present invention can be sprayed at temperatures as low as 125°C (257°F).

Hot melt adhesive compositions for producing disposable articles use block copolymers, especially triblock copolymers, comprising terminal poly(styrene) blocks and one or more central poly(isoprene) blocks. More specifically, triblock copolymers having a poly(styrene) content of 25 wt% to 35 wt% and a total apparent molecular weight of 100,000 daltons (Da or grams per mole (g/mol)) to 300,000 Da are typical. It is used in hot melt adhesive compositions in the diaper industry in two ways:

1) As an assembly adhesive for bonding the diaper poly(ethylene) main frame, and

2) Elastic thread (fiber) used as waist and leg bands or as an attachment adhesive to bond films.

Suitable adhesives are characteristically transparent or light colored, have low odor, are sprayable as hot melt adhesives, exhibit good adhesion to poly(olefin) films, and do not bleed into nonwoven backsheets. Additionally, these adhesives usually exhibit a melt viscosity that allows spray application in the temperature range of 160°C to 180°C. Additionally, another desirable property of these adhesives is that they are relatively inexpensive.

Elastic attachment adhesives are used to bond elastic yarns to polyethylene and nonwoven films to form elastic waist or leg bands for diapers or hygiene products. The plurality of elastic yarn strands are stretched, typically 300% stretched, and coated with an adhesive composition at a temperature of about 160° C. to 180° C. immediately prior to being embedded within the poly(olefin) and nonwoven film. Like structural adhesives, these adhesives are typically sprayed in various patterns, such as a spiral or wrap around pattern. When the elastic ends are cut later in the process, the composite shrinks and wrinkles the nonwoven and poly(olefin) films to form an elastic band.

Although specially designed block copolymers exhibit an acceptable hot melt viscosity/temperature profile and the viscosity is sufficiently low to allow processing to be effective at hot melt temperatures below 180°C, which are commonly applied, processing along with other desirable properties described above. Block copolymers that demonstrate processing efficiency remain economically desirable.

The physical requirements for elastic attachment adhesives are:

1) High cohesive strength and good creep resistance;

2) the ability to adhere strongly to more polar elastic materials such as polyurethane in addition to polyethylene and polypropylene nonwoven films;

3) low melt viscosity and resulting high melt flow rate - low temperature applications typically require a viscosity range of about 10,000 centipoise (cps) to 15,000 cps at spray nozzle temperature;

4) Sufficient melt viscosity balanced against maintaining sufficient pump pressure; and

5) High melt strength for spray applications.

It will be appreciated that relatively low hot melt viscosity allows for high production rates in diaper manufacturing lines without producing significant amounts of off-spec product. Problems that usually cause these off-spec products can be, for example, reduced adhesive viscosity, adhesive discoloration, polyethylene film damage, or char formation. Accordingly, development efforts in diaper manufacturing continue today toward the down-gauging of polyolefin films and elastic yarns to require spray application temperatures as low as possible while maintaining adequate adhesion and creep resistance.

The present invention provides improved adhesive compositions that exhibit suitable viscosity at temperatures ranging from about 125° C. to about 140° C. to avoid the problems described above while allowing sprayability at higher production rates.

The present invention includes at least one block copolymer and at least one tackifying resin, wherein the at least one block copolymer comprises (i) one or more blocks of a polymerized alkenyl arene monomer (A block), (ii) a polymerized conjugated diene. comprising one or more blocks of monomer (B block) and optionally at least one low molecular weight (relative to B block) polymerized conjugated diene block (C block), wherein the A, B and C blocks are related in composition and molecular weight. Adhesive compositions, which may vary independently from each other, are disclosed.

Additionally, the present invention discloses a diaper with leg holes and waist holes for a person that includes elastic attachments around the leg holes and waist holes of the diaper, wherein the elastic attachments are secured to the diaper by an adhesive composition, wherein the adhesive composition comprises: comprising at least one block copolymer, at least one end block resin, at least one tackifier, and at least one oil, wherein the at least one block copolymer is (i) at least one block of polymerized alkenyl arene monomer (A block) , (ii) one or more blocks of polymerized conjugated diene monomers (B blocks) and optionally at least one low molecular weight (relative to B block) polymerized conjugated diene block (C blocks), wherein A, B and The C blocks may vary independently from each other with respect to composition and molecular weight, and based on the total weight of the adhesive composition, the block copolymer is present in the range of about 10 to about 30 wt%, and the tackifier is present in the range of about 25 wt% to about 25 wt%. The at least one end block resin is present at about 70 wt%, the one or more end block resins at about 10 wt% to about 40 wt%, and the one or more oils at about 5 wt% to about 30 wt%.

Figure 1 is a plot of hot melt viscosity versus temperature for formulations with a polymer content of 20 wt%.
Figure 2 is a plot showing hot melt viscosity versus temperature performance at 20 wt% polymer content.

The main ingredients used in the adhesive composition of the present invention are block copolymer (component 1), one or more tackifying resins (or combination of resins) (component 2), plasticizer (component 3) and antioxidant (component 4). According to one aspect, the compositions of the present invention further comprise an optional alkenyl arene homopolymer or copolymer (component 5). In particular, note that the block copolymer itself contains alkenyl arene polymer blocks. This should not be confused with optional component (5) which does not include other components of the block copolymer (component 1).

The block copolymer of the present invention (component 1) consists of a block (A) of a polymerized alkenyl arene monomer or a mixture of polymerized alkenyl arene monomers, and a block (B) of a polymerized conjugated diene monomer or a mixture of polymerized conjugated diene monomers. ) are displayed as structures containing. Block C is an optional low molecular weight (relative to block (B)) polymerized conjugated diene or a mixture of polymerized conjugated dienes. Suitable structures include ABA prepared by sequential polymerization; (AB) _n ABAC prepared by sequential polymerization; CABAC prepared by sequential polymerization; (CAB) _{n ( AB} ) n The sum of cannot exceed the valency of the coupling agent; ₍ CAB) _n and the sum of n+m cannot exceed the valence of the coupling agent. If the coupling agent is polymerizable (e.g. divinyl benzene), the valence requirement is not applicable. In all of the above structures each A, B and C block may differ from the other A, B and C blocks with respect to composition and molecular weight.

The (A) blocks of the polymerized alkenyl arene monomer may be styrene, alpha-methylstyrene, para-methylstyrene, vinyl toluene, vinyl naphthalene, para-butyl styrene, or combinations thereof. According to one view, the A block is prepared by polymerization of styrene. A blocks may have a peak molecular weight of about 4,000 g/mol to about 30,000 g/mol, alternatively about 5,000 g/mol to about 15,000 g/mol.

The (B) blocks of the conjugated diene can be 1,3-butadiene and substituted butadiene such as isoprene, piperylene, 2,3-dimethyl-1,3-butadiene and 1-phenyl-1,3-butadiene or combinations thereof. there is. According to one aspect, the B block of the polymerized conjugated diene comprises polymerized isoprene. The B block may have a peak molecular weight of about 20,000 g/mol to about 200,000 g/mol, or alternatively about 40,000 g/mol to about 120,000 g/mol.

The C block(s) of the optional polymerized conjugated diene include 1,3-butadiene and substituted butadienes such as isoprene, piperylene, 2,3-dimethyl-1,3-butadiene and 1-phenyl-1,3-butadiene. , or a combination thereof. According to one aspect, the (C) block(s) of the polymerized conjugated diene comprises butadiene. The C block may have a peak molecular weight of about 2000 g/mol to about 30,000 g/mol, or alternatively about 2000 g/mol to about 10,000 g/mol.

According to one view, the molecular weight of the B block is greater than or equal to the molecular weight of the C block. When using a coupling agent, there will be a C-A-B type triblock or A-B type diblock. These triblocks or diblocks may be present in the block copolymer (Component 1) in an amount between about 5 wt% and about 35 wt% based on the total weight of the block copolymer.

The melt flow rate range of the block copolymer (component 1) is about 20 g/10 min at 200°C with a mass of 5 kg. It may be from about 100 g/10 min. According to an alternative view, the melt flow rate is about 30 g/10 min at 200°C under 5 kg mass. to about 40g/10min.

According to one aspect, the structure of the block copolymer (component 1) has at least one internal B block within the structure and one terminal A block within the structure. According to an alternative view, the structure of the block copolymer (component 1) has at least one internal B block in the structure and one terminal C block in the structure (e.g., A-B-A-C or C-A-B-A-C). In these respects, a structure with a terminal C block may be such that the C block has a lower molecular weight than any internal B block.

In the block copolymer (component 1) according to the present invention, the poly(styrene) content (which may include optional comonomers) ranges from about 28 wt% based on the total weight of the block copolymer (i.e. component 1). about 50 wt%, alternatively about 28 wt% to about 35 wt%, or alternatively about 29 wt% to about 33 wt%.

The block copolymer (component 1) applied to the adhesive composition according to the present invention has a number average molecular weight (M _n expressed based on polystyrene) according to the literature (RUNYON, James R. et al., Multiple detectors for molecular weight and composition analysis of copolymers is about 150,000 g/ as measured by gel permeation chromatography (GPC) using the method described in Journal of Applied Polymer Science, 1969, vol. 13, no. 11, p. 2359-69. mol to about 500,000 g/mol, or alternatively from about 100,000 g/mol to about 230,000 g/mol.

As used herein, the term “molecular weight” refers to the true molecular weight (g/mol) of a polymer or copolymer block. Molecular weights recited in the specification and claims can be determined by gel permeation chromatography (GPC) using polystyrene calibration standards as performed in accordance with ASTM D5296. GPC is a method in which polymers are separated according to molecular size, with the largest molecules eluting first. The chromatograph is calibrated by commercially available polystyrene molecular weight standards. The molecular weight of the polymer measured using this calibrated GPC is the styrene equivalent molecular weight. Styrene equivalent molecular weight can be converted to true molecular weight when the styrene content of the polymer and the vinyl content of the diene segments are known. The detector used is preferably a combined ultraviolet and refractive index detector. Molecular weights expressed herein are measured at the peak of the GPC record and converted to the true molecular weight, commonly referred to as “peak molecular weight.”

In one aspect of the invention, block copolymers (component 1) that are structures having terminal C block(s) (e.g., C-A-B-A-C) have a ratio of the molecular weight of the terminal C block to the molecular weight of the internal B block(s) of about 0.01:1. to about 1:1, or alternatively from about 0.05:1 to about 0.1:1. In another aspect of the invention, a block copolymer (component 1) (e.g., C-A-B-A-C) that is structured with terminal C block(s) has a terminal copolymer of a molecular weight that is from about 1% to about 20% of the molecular weight of the internal B block(s). Holds C blocks.

In one aspect, the end block resin is a high T _g , low MW styrenic resin (e.g., alpha-methyl styrene resin) that increases creep performance. Examples of commercially available resins used in end block resins include, but are not limited to, KRISTLEX 3085.

The block copolymer (component 1) of the present invention has a melt flow index of about 18 g/10 min, measured at 200°C under a 5 kg mass according to ASTM D-1238. to about 100g/10min. It is a range. Melt flow rates within this range will generally provide the hot melt adhesive of the present invention with a viscosity of about 10,000 cps or less at about 130°C. It has been observed that hot melt adhesives with a viscosity of less than about 10,000 cps at about 130°C can be sprayed at temperatures ranging from about 125°C to about 138°C.

The block copolymers of the present invention (component 1) can be produced sequentially or by coupling, as noted in reissued U.S. Pat. No. RE 27,145, which is incorporated herein by reference. Sequentially means that each block copolymer starts with an end block polymer (polymerizing the monomer into a block polymer), which is then attached to the next monomer that is polymerized into a block polymer, forming the copolymer until the desired structure is completed. Shiki means manufactured by anionic polymerization. When block copolymers according to the present invention are manufactured by coupling living block copolymers with a coupling agent, various block copolymers are joined together through a coupling agent. Coupling agents include any chemical species that has multiple functional groups and is reactive in an additive fashion with the living anionic chain end.

Suitable coupling agents are dihalo alkanes, silicon halides, siloxanes, polyfunctional epoxides, silica compounds, esters of monohydric alcohols and carboxylic acids, and epoxidized oils. Other non-limiting examples of coupling agents include divinylbenzene, tetra-alkoxysilanes such as tetra-ethoxysilane and tetra-methoxysilane, alkyl-trialkoxysilanes such as methyl-trimethoxy silane, dimethyl adipate and diethyl. These include aliphatic diesters such as adipates, and diglycidyl aromatic epoxy compounds such as diglycidyl ether derived from the reaction of bisphenol A and epichlorohydrin.

In one aspect, the block copolymer (Component 1) is present in the composition in an amount of from about 10 wt% to about 60 wt%, alternatively from about 18 wt% to about 50 wt%, based on the total weight of the adhesive formulation. .

The tackifying resin (component 2) used in the hot melt adhesive composition of the present invention may be any resin that is compatible with the other components of the hot melt adhesive. These resins include modified C ₅ hydrocarbon resins (C ₅ /C ₉ resins), styrenated terpene resins, fully or partially hydrogenated C ₉ hydrocarbon resins, hydrogenated cycloaliphatic hydrocarbon resins, hydrogenated aromatic modified cycloaliphatic hydrocarbon resins, and Modified aliphatic hydrocarbon resins, such as combinations thereof.

Examples of tackifying resins used as component (2) include, but are not limited to, water white hydrocarbon resins of the ESCOREZ™ resin series such as ESCOREZ™ 5600, ESCOREZ™ 5400, ESCOREZ™ 5300, etc. available from ExxonMobil Chemical Company. , or hydrocarbon resins from the REGALITE™ resin series, such as REGALITE™ 1090, REGALITE™ 7100 and REGALITE™ S-5100 resins, or the EASTOTAC™ resin series, such as EASTOTAC™ 100W, both available from ExxonMobil Chemical Company, or Arakawa Includes the ARKON™ resin series such as ARKON™ P and M resins available from Chemical Company.

In one aspect, the one or more tackifying resins are solid tackifying resins having a ring and ball softening point ranging from about 90° C. to about 105° C. and an aromatic proton nuclear magnetic resonance (H-NMR) content of 0 to about 30%. , or alternatively 0 to about 12%.

In the hot melt adhesive composition of the present invention, the one or more tackifying resin components (2) are present in an amount of about 35 wt% to about 60 wt% based on 100 wt% of the hot melt adhesive composition, or in other words, based on the total weight of the hot melt adhesive composition. In an alternative aspect, component (2) is present in an amount of 40 wt% to 50 wt% based on the total weight of the hot melt adhesive composition.

Suitable plasticizers (component 3) primarily have a carbon aromatic distribution of less than about 5%, alternatively less than about 2%, alternatively less than 0%, as measured in accordance with DIN 51378, and a glass transition temperature as measured by differential scanning calorimetry. and plasticized oils that are paraffinic or naphthenic in nature, such as below about -55°C, or alternatively below about -65°C. Examples of plasticizers (component 3) suitable for use in the present invention are available from the Royal Dutch/Shell Group of companies and include SHELLFLEX™, CATENEX™, and ONDINA™ oils. Other oils include KAYDOL™ oil (Witco), TUFFLO™ oil (Arco), NYPLAST™ (NYNAS) or CALSOL™ 5550 or 5555 (CALUMET LUBRICANTS), or Sontex™ 450 or Nyflex™ 222B or Drake oil (Penreco Co.). Includes.

Additionally, other plasticizers may be included in the hot melt adhesive composition, including olefin oligomers; low molecular weight polymers (up to 30,000 g/mol), such as liquid polybutene, liquid polyisoprene copolymer, liquid styrene/isoprene copolymer or liquid hydrogenated styrene/conjugated diene copolymer; Vegetable oils and their derivatives; Alternatively, there are paraffin and microcrystalline waxes.

The hot melt adhesive composition according to the present invention includes a plasticizer (component 3) present in an amount of about 10 wt % to about 25 wt % based on the total weight of the hot melt adhesive composition.

It will be appreciated that each block copolymer of component (1) may be pre-blended with a small amount of plasticizer by the manufacturer of the copolymer. This small amount helps the flowability of the block copolymer. This small amount, if present, is included in the calculated total amount of plasticizer.

The hot melt adhesive of the present invention may additionally contain an antioxidant (component 4). Most antioxidants fall into the category of primary or secondary antioxidants and have different functions due to their different chemical structures. Primary antioxidants are usually hindered phenols or arylamines. Primary antioxidants scavenge alkoxy radicals and peroxy radicals. Any primary antioxidant that is compatible with the styrenic block copolymer may be included in the compositions of the present invention. Primary antioxidants sold by BASF under the trade name IRGANOX may be suitable for use in the present invention, such as 1010, 1076 and 1330.

Additionally, secondary antioxidants may be used in conjunction with primary antioxidants. Secondary antioxidants are generally phosphites and thiosynergists. Secondary antioxidants capture hydroperoxides produced during the autoxidation cycle of polymers exposed to heat and oxygen. Various compositions sold under the trade name IRGAFOS™ may be suitable, which are also BASF products. IRGAFOS™ 168 and analogs thereof may be suitable carbon radical scavengers of the present invention. Carbon radical scavengers suitable for use in the present invention are available from Sumitomo Chemical under the trade name SUMILIZER™.

Additionally, antioxidants can be added to protect the adhesive from degradation induced by heat, light and processing. Several types of antioxidants can be used, such as primary antioxidants such as hindered phenols or secondary antioxidants such as phosphite derivatives or blends thereof.

Another example of a commercially available antioxidant is IRGANOX® 565 (2.4-bis-(n-octylthio)-6-(4-hydroxy-3,5-di-tert-butylanilino)- from Ciba-Geigy. 1,3,5-triazine), IRGANOX™ 1010 (tetrakis-ethylene-(3,5-di-tert-butyl-4-hydroxy-hydrocinnamate)methane) from Ciba-Geigy and Uniroyal Includes POLYGARD™ HR (tris-(2,4-di-tert-butyl-phenyl)phosphite). Additionally, other antioxidants developed to protect the gelation of polybutadiene segments can also be used, such as SUMILIZER™ GS (2[1-(2-hydroxy-3,5-di-ter-pentylphenyl) from Sumitomo ) ethyl)]-4,6-di-tert-pentylphenylacrylate); SUMILIZER™ T-PD (pentaerythrityltetrakis(3-dodecylthiopropionate)) manufactured by Sumitomo; Or there is a combination thereof.

The one or more antioxidants are optionally present in an amount of about 0.01 wt% to about 2 wt% antioxidant based on the total weight of the hot melt adhesive composition. In another aspect of the invention, component (4) is present in an amount of about 0.5 wt% to about 1.5 wt% based on the total weight of the hot melt adhesive composition.

In one aspect, the alkenyl arene homopolymer or copolymer (component 5), if present, is present in an amount of up to about 35 wt% based on the total weight of the hot melt adhesive composition. Alternatively, the alkenyl arene homopolymer or copolymer (component 5), if present, is present in an amount of about 20 wt% to about 25 wt%. Examples of commercially available alkenyl arene homopolymers (component 5) suitable for use in the present invention include ENDEX™ 155 or 160, KRISTALEX™ 3085, available from Eastman Chemical Company, primarily alpha methyl styrene.

There are no particular restrictions on the manufacturing process of the hot melt adhesive composition of the present invention. Accordingly, any process may be used to combine components 1 to 4 (or 1 to 5) of the hot melt adhesive composition, examples of which include mechanical mixing processes using rolls, Banbury mixers, or Dalton kneaders. there is. Other methods of combining the components of a hot melt adhesive include the hot melt process, wherein heating and mixing are carried out using a melt kettle equipped with an agitator, such as a turbo mixer, a high shear Z-blade mixer or a single or twin screw extruder, or a suitable solvent. and a solvent process in which the blended ingredients are poured and stirred to obtain an intimate solution of the pressure sensitive adhesive composition (known as a hot melt adhesive composition).

Various other rubber components may be included in the hot melt adhesive composition of the present invention as needed to modify the tack, odor or color of the hot melt adhesive. The hot melt adhesive composition according to the invention is effectively applied as an assembly adhesive composition or an attachment adhesive composition for assembling (e.g. as described herein) sanitary articles, especially diapers, comprising a polyethylene backbone and at least one non-woven lining member. .

The formulated hot melt adhesive composition according to the present invention has the following advantages: improved creep properties when bonding elastic fibers; and was found to exhibit good sprayability, especially at low temperatures.

Example

The following examples are intended to illustrate the present invention. These examples are not intended to limit the scope of the present invention and should not be construed as such.

Three types of styrene/isoprene multiblock copolymers (with similar molecular weights but different melt flow rates) were prepared, and their properties are presented in Table 1.

Sample display polystyrene block 1
Approximate M _n (kDa) polystyrene block 2
Approximate M _n (kDa) Rubber block B+C
Approximate M _n (kDa) F-436 15 13 64 Campaign 35 15 14 72 Campaign 55 15 14 61 Kraton™ D1165(A) 15 80 15

The primary synthesis was performed in a small-scale pilot reactor and produced a model block copolymer designated F-436. Subsequently, two large-scale samples (approximately 230 kg scale) were prepared from a semi-commercial reactor system and were referred to as campaigns 25 and 55. This gave three variants; Campaign 55 material showed the most balanced properties in terms of high melt flow rate and tensile strength. Comparative data are presented in Table 2.

polymer location of production Melt flow rate at 200℃/5kg, g/10min Tensile strength of compression molded samples ^*** (psi) elastic attachment
Laminate testing F-436 pilot 26 3830 No, sample size is too small Campaign-25 Semi-commercial scale 18 2230 yes Campaign-55 Semi-commercial scale 36 3715 Yes, the form with the best overall performance Comparative example A commercial scale 7 1735 Yes (see Table 5)

^*** Tensile test conditions: ASTM D412 Type D die, gauge length = 1", x-head speed = 10"/min, 50 lb load cell, see Appendix 3.0.

adhesive performance

Table 3 shows the starting formulations used to select the hot melt viscosity of Campaign-55 and Comparative Example A. These formulations were mixed in a Sigma blade mixer at 160°C.

Figure 2 shows final hot melt viscosity vs. Indicates temperature performance. In fact, Campaign-55 consistently met the criteria for low hot melt viscosity at a minimum of 120°C.

Substance, wt% F1 F2 F3 F4 F5 F6 Campaign-55 (MFR~36) 20 15 Campaign 25 (MFR~18) 20 15 Comparative example A 20 15 Eastotac 100W mid-block resin 45 45 45 45 45 45 Kristalex 3085 End Block Resin 20 25 20 25 20 25 Sontex 450 Oil 14.9 14.9 14.9 14.9 14.9 14.9 Irganox 1010 0.1 0.1 0.1 0.1 0.1 0.1 SAFT for Mylar (2.54 cm square, 0.5 kg), (℃) 69 60 73 69 79 73

The shear adhesion failure temperature (SAFT) for Mylar of each hot melt formulation was investigated as an indicator of shear resistance at elevated temperatures. Lower viscosity formulations showed lower SAFT, suggesting that structural changes that benefit viscosity slightly offset this property (this data is presented in Table 3). Since the EAA laminate needs to function only at body temperature (i.e., 37°C), low SAFT may not be a problem. When the Holding Power (HP) was investigated (SAFT-like shear test, only at 25°C), the HP for stainless steel was It's been over 10,000 minutes. Figure 1 is a plot of hot melt viscosity versus temperature for the highest polymer content formulations (see Table 3). From this plot it is clear that Campaign-55 with a polymer content of 20 wt% exhibits the lowest viscosity in the temperature range presented.

Samples from Campaign-55 were further evaluated by creating an elastic laminate. A 2.0 kg scale formulation was prepared and used for spraying experiments in producing elastic laminates. It should be noted that the two control formulations cannot be spray applied at temperatures below 150°C. Comparative Example A showed higher creep compared to commercially available styrene-isoprene-styrene block copolymers. Creep was measured as follows: Six structures were cut to size approximately 25 mm wide and 400 mm long. One end was stapled to test cardboard marked with three sets of lines. The first line was the zero line located approximately 15 mm from one edge of the cardboard. The second line was 285 mm from the zero line and the third line was 300 mm from the zero line and approximately 15 mm from the edge of the cardboard opposite the zero line. The first end of the structure was stapled between the zero line and the edge of the cardboard within 15 mm. The structure was then stretched to full extension with no gathers in the laminate and marked with a pen at the 300 mm mark. The structure was then relaxed until the mark was above the 285 mm line. This allowed the structure to be stretched to 95% of its total elongation. After the complete set was fastened, a laser blade was used to cut along each elastic yarn at both ends. One set of cuts was made at the zero line and the other set was made at the 285 mm line. The test panel was then placed in a forced air oven set at 100±1°F for 4 hours. After 4 hours, the test panel was removed and marks were made at each end of the structure where the elastic yarn no longer wrinkled the film and fabric. Each label represents the average of three strands of elastic yarn at each end. The distance between the two marks was then measured and creep% was calculated using the formula: Creep% = Initial(285) - Final/Initial(285) x 100.

ingredient
wt% HL-1486
Commercial product ^* sample 1 sample 2 sample 3 block copolymer N.A. 20 15 15 Kristalex 3085 N.A. 15 25 15 Endex 160 (RBSP
~160℃) N.A. 5 5 Eastotac H100 N.A. 45 45 50 Nyflex 222B N.A. 14.5 14.5 14.5 Irganox 1010 N.A. 0.5 0.5 0.5

^* HB Fuller, based on SIS, but composition unknown.

Figure 2 is a plot showing the hot melt viscosity of EAA formulations mixed for spray lamination experiments - formulations HL1486 (commercial control), 68-6-2 and 68-6-4 were selected for the final lamination experiment.

sample number application temperature
(℃) Cloth weight
(gsm CF or mg/lm/strand SW) creep
Average 32" nib Standard Deviation
32" nib average
19.25" nib Standard Deviation
19.25" nib % improvement by reducing nip distance HL1486
control group 160 50 8.3% 0.0256 3.1% 0.0031 5.2% Comparative example A 160 50 13.9 0.0233 N.T. N.T. N.A. sample 4 130 50 NT ^* N.T. 31.8% 0.0870 N.A. sample 4 140 50 N.T. N.T. 34.7% 0.6509 N.A. sample 4 150 50 N.T. N.T. 9.0% 0.0093 N.A. sample 2 130 50 70.8% 0.1226 50.6% 0.1408 20.2% sample 2 140 50 66.1% 0.0930 50.2% 0.0819 15.9% sample 2 150 50 13.0% 0.0253 7.8% 0.0177 5.3%

^* Not tested - These were new formulations that had not been previously tested at a 32" nip distance.

Campaign-55 as the base polymer of EAA formulations was observed to have the following advantages compared to Comparative Example A:

* Lower melt viscosity

* Higher tensile strength (although SAFT was lower compared to Comparative Example A as an adhesive)

*Comparative Example A Neither the control nor the commercial HL1486 formulation could be spray applied below 150°C.

* Variation in open time (nip gap) improves creep performance at lowest application temperatures.

As such, it is clear that according to the present invention, an adhesive composition, a diaper, and a method for manufacturing a diaper have been provided that fully satisfy the above-mentioned objects, objectives, and advantages. Although the invention has been described in connection with specific embodiments thereof, it will be apparent to those skilled in the art that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the preceding description. Accordingly, all such alternatives, modifications and variations are intended to be included within the spirit and broad scope of the subsequent claims.

Additional commencement

The aspects of the invention listed below are provided as non-limiting examples.

Comprising one or more block copolymers and one or more tackifying resins, wherein the one or more block copolymers include (i) one or more blocks of polymerized alkenyl arene monomers (A blocks), and (ii) one or more blocks of polymerized conjugated diene monomers. or more blocks (B blocks) and, if appropriate, at least one polymerized conjugated diene block (C block) of low molecular weight (relative to the B block), wherein the A, B and C blocks are independent of each other with respect to composition and molecular weight. A first aspect is an adhesive composition, which may vary from:

The block copolymer is ABA; A structure _selected from the group consisting _{of ( AB ) n} is 2 to 20, X is a coupling agent, and the sum of n+m cannot exceed the valency of the coupling agent.

A third aspect of the adhesive composition of the first or second aspect, wherein the alkenyl arene monomer is styrene, alpha-methylstyrene, para-methylstyrene, vinyl toluene, vinyl naphthalene, para-butyl styrene, or combinations thereof.

A fourth aspect of the adhesive composition of the third aspect, wherein the alkenyl arene monomer is styrene.

The first to second aspects, wherein the conjugated diene monomer is 1,3-butadiene, substituted butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, or a combination thereof. A fifth aspect, which is the adhesive composition of any one of the four aspects.

A sixth aspect, which is the adhesive composition of any one of the first to fifth aspects, wherein the conjugated diene monomer is isoprene.

A seventh aspect, wherein the coupling agent is the adhesive composition of any one of the first to sixth aspects, wherein the coupling agent contains several functional groups and includes any chemical species that reacts in an additive manner with the living anionic chain ends.

An eighth aspect, wherein the A block is the adhesive composition of any one of the first to seventh aspects, wherein the A block has a peak molecular weight of about 4,000 g/mol to about 30,000 g/mol.

The ninth aspect is the adhesive composition of the eighth aspect, wherein the B block has a peak molecular weight of about 20,000 g/mol to about 200,000 g/mol.

A tenth aspect of the adhesive composition of the ninth aspect, wherein the C block has a peak molecular weight of about 2,000 g/mol to about 30,000 g/mol.

The eleventh aspect is the adhesive composition of the ninth aspect, wherein the structure bearing the terminal C block(s) has a molecular weight ratio to the internal B block(s) of 0.01:1 to 1:1.

A twelfth aspect is the adhesive composition of the tenth aspect, wherein the molecular weight ratio of the terminal C block(s) to the internal B block(s) is in a ratio of 0.05:1 to 0.1:1.

A thirteenth aspect, which is the adhesive composition of any of the first to twelfth aspects, having at least one terminal C block in the structure and one terminal A block in the structure.

A fourteenth aspect, which is the adhesive composition of any one of the first to thirteenth aspects, wherein the structure having a terminal C block has a molecular weight lower than that of any internal B block.

It further comprises one or more terminal block resins and one or more oils, wherein the block copolymer is present in the range of about 15 wt% to about 50 wt% and the tackifier is present in the range of about 35 wt% to about 60 wt%. and the one or more end block resins are present in an amount ranging from about 0 to about 35 wt%, and the one or more oils are present in an amount ranging from about 10 wt% to about 25 wt%, with each wt% representing the total weight of the adhesive composition. The 15th aspect, which is the adhesive composition according to any one of the 1st to 14th aspects, which is the standard.

Aspects 1 to 15 further comprising from about 0.01 wt% to about 2 wt% of one or more primary antioxidants and from about 0.01 wt% to about 2 wt% of secondary antioxidants, based on the total weight of the adhesive composition. Aspect 16, which is the adhesive composition of any one of the aspects.

A seventeenth aspect, wherein the adhesive is the adhesive composition of any one of the first to sixteenth aspects, wherein the adhesive is a hot melt adhesive for elastic attachment. In one embodiment, the composition has creep of 30% or less; SAFT between 30°C and 60°C; Melt flow rate approximately 10 g/10 min measured at 200°C under 5 kg mass according to ASTM D-1238. to about 50g/10min. range; The tensile strength measured according to ASTM D412 is about 1,000 psi to about 5,000 psi.

An eighteenth aspect, a method of using the adhesive composition described in the sixteenth aspect, wherein the adhesive is sprayed onto the elastic attachment and allowed to dry.

A 19th aspect is the method of the 16th aspect, wherein the adhesive is sprayed onto the elastic attachment at a temperature between about 125°C and 138°C.

A 20th aspect, which is the method of the 18th or 19th aspect, wherein the adhesive is sprayed onto the elastic attachment of the diaper at a temperature between about 130° C. and about 135° C.

A diaper with leg openings and waist openings for a human, comprising elastic attachments around the leg openings and waist openings of the diaper, wherein the elastic attachments are secured to the diaper by an adhesive composition, the adhesive composition comprising one or more block copolymers [ At this time, the one or more block copolymers include (i) one or more blocks of polymerized alkenyl arene monomers (A blocks), (ii) one or more blocks of polymerized conjugated diene monomers (B blocks), and, if desired, at least one block. a polymerized conjugated diene block (C block) of low molecular weight (relative to the B block), wherein the A, B and C blocks may independently differ from each other with respect to composition and molecular weight], one or more terminal block resins, one At least one tackifier, and at least one oil, wherein, based on the total weight of the adhesive composition, the block copolymer is present in the range of about 10 to about 30 wt%, and the tackifier is present in the range of about 25 wt% to about 70 wt%. wt%, wherein the one or more end block resins range from about 10 wt% to about 40 wt%, and the one or more oils range from about 5 wt% to about 30 wt%. Perspective 21, which is diapers.

A twenty-second aspect is the diaper of the twenty-first aspect, wherein the A block has a peak molecular weight of about 4,000 g/mol to about 30,000 g/mol.

A twenty-third aspect wherein the B block is the diaper of the twenty-first or second aspect, wherein the B block has a peak molecular weight of about 20,000 g/mol to about 200,000 g/mol.

A 24th aspect, which is the diaper of any one of the 21st to 23rd aspects, wherein the structure having the terminal C block(s) has a molecular weight ratio of 0.01:1 to 1:1 compared to the internal B block(s).

A twenty-fifth aspect, which is the diaper of any of the twenty-first to twenty-fourth aspects, wherein the ratio of terminal C block(s) to internal B block(s) is in a ratio of 0.05:1 to 0.1:1.

Claims (25)

One or more block copolymers and one or more tackifying resins
As an adhesive composition comprising,
wherein the one or more block copolymers comprise:
(i) one or more A blocks, which are blocks of polymerized alkenyl arene monomers,
(ii) at least one B block, which is a block of polymerized conjugated diene monomers, and
(iii) at least one C block, which is a block of polymerized conjugated diene having a lower molecular weight compared to the B block;
The A, B and C blocks may independently differ from each other with respect to composition and molecular weight,
The block copolymer has a structure _selected from the group consisting _of ABAC, CABAC, ( _{CAB ) n}
The at least one A block has a peak molecular weight of 4,000 g/mol to 30,000 g/mol, the at least one B block has a peak molecular weight of 40,000 g/mol to 120,000 g/mol, and the molecular weight of the C block is 1% of the molecular weight of the B block. to 20%, n and m are each independently 2 to 20, X is a coupling agent, and the sum of n+m cannot exceed the valence of the coupling agent,
Adhesive composition. The adhesive composition of claim 1, wherein the alkenyl arene monomer is selected from styrene, alpha-methylstyrene, para-methylstyrene, vinyl toluene, vinyl naphthalene, para-butyl styrene, or combinations thereof. The method of claim 1, wherein the conjugated diene monomer is 1,3-butadiene, substituted butadiene, isoprene, piperylene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, or these. An adhesive composition selected from combinations of: The adhesive composition of claim 1, wherein the coupling agent comprises a chemical species that possesses a plurality of functional groups and reacts in an additive manner with the living anionic chain-end. The adhesive composition of any one of claims 1 to 4, wherein the C block has a peak molecular weight of 2,000 g/mol to 30,000 g/mol. 5. The structure according to any one of claims 1 to 4, wherein in said structure bearing terminal C block(s), the molecular weight of the terminal C block(s) of the structure is compared to the molecular weight of the internal B block(s) of the structure. The adhesive composition has a ratio of 0.01:1 to 1:1. 5. The adhesive composition according to any one of claims 1 to 4, wherein the structure possesses at least one terminal C block and one terminal A block. The adhesive composition according to any one of claims 1 to 4, wherein the structure has a terminal C block with a lower molecular weight than the internal B block in the structure. 5. The adhesive composition according to any one of claims 1 to 4, wherein the adhesive composition further comprises one or more end block resins and one or more oils,
Based on the total weight of the adhesive composition, the block copolymer is present in the range of 15 wt% to 50 wt%, the tackifying resin is present in the range of 35 wt% to 60 wt%, and the one or more end blocks wherein the resin is present in the range of 0 to 35 wt%, and the one or more oils are present in the range of 10 wt% to 25 wt%,
Adhesive composition. 5. The method according to any one of claims 1 to 4, wherein, based on the total weight of the adhesive composition, 0.01 wt% to 2 wt% of one or more primary antioxidants and 0.01 wt% to 2 wt% of secondary oxidation antioxidants. An adhesive composition further comprising an inhibitor. The adhesive composition according to any one of claims 1 to 4, wherein the adhesive is a hot melt adhesive for elastic attachment. A method of using the adhesive composition according to any one of claims 1 to 4, comprising:
Method of use, wherein the adhesive composition is sprayed onto the elastic attachment and allowed to dry. 13. A method of use according to claim 12, wherein the adhesive composition is sprayed onto the elastic attachment at a temperature between 125°C and 138°C. 1. A diaper with leg openings and waist openings for a human, comprising elastic attachments around the leg openings and waist openings of the diaper,
The elastic attachment is secured to the diaper by an adhesive composition,
The adhesive composition includes:
- at least one block copolymer comprising:
(i) one or more A blocks, which are blocks of polymerized alkenyl arene monomers,
(ii) at least one B block, which is a block of polymerized conjugated diene monomers, and
(iii) at least one C block, which is a block of polymerized conjugated diene having a lower molecular weight compared to the B block; Here, the A, B and C blocks may independently differ from each other with respect to composition and molecular weight, and the block copolymer may be ABAC, _CABAC , (CAB _{) n CAB} ) _n 120,000 g/mol, the molecular weight of the C block is 1% to 40% of the molecular weight of the B block, n and m are each independently 2 to 20, X is a coupling agent, and the sum of n + m is the coupling agent cannot exceed the valence of;
- one or more end block resins;
- one or more tackifiers; and
- one or more oils;
Based on the total weight of the adhesive composition, the block copolymer is present in the range of 10 to 30 wt%, the tackifier is present in the range of 25 wt% to 70 wt%, and the one or more terminal block resins are present in the range of 10 to 30 wt%. wherein the one or more oils are present in the range of 5 wt% to 30 wt%,
diaper. 15. The method of claim 14, wherein in said structure bearing terminal C block(s), the ratio of the molecular weight of the terminal C block(s) of the structure to the molecular weight of the internal B block(s) of the structure is from 0.01:1 to 1:1. In, diapers. delete delete delete delete delete delete delete delete delete delete